Since there didn’t seem to be a good single source of links to individual 3D buildings, I collected suggestions from the community and then created this wiki page. There is some very nice work here by OSM users. My favorite is Coors Field, but I’m prejudiced
I’ve never come across a ferris wheel in OSM with 3D elements added. I doubt it would qualify as a “building” per OSM standards. As far as I understand tunnels, they would not be modeled in 3D either as, I believe all 3D structures would be modeled above ground. There are undergound structures described as buildings, for example: https://www.openstreetmap.org/edit#map=21/37.78930/-122.40117 This building’s levels are from max level -1 to min level -3. In cases where bridges serve as buildings, there are examples, such as here: https://demo.f4map.com/#lat=51.5057311&lon=-0.0754226&zoom=19&camera.phi=36.784